America, that country's favourite myth insists, was built by the individual: the 'calm, mature' man praised by de Tocqueville; Emerson's self-reliant 'true prince'. But in Joshua Ferris's debut novel of life and death in an ailing Chicago ad agency, times have changed. Rugged founding heroes give way to polo-shirted drones; horizons shrink to the fibreboard walls of an office cubicle; and, in an attention-grabbing display of virtuosity, the reassuring omniscient narrator is replaced by a stressed-out, first-person plural.

Ferris's 'we' is a fractious, hydra-headed array of copywriters and art directors, from upbeat networker Karen Woo to grizzled, reclusive Frank Brizzolera. Their days of extravagant anomie are shaped by a patchwork of kitchen gossip, emails and snippets that filter down from the office of their forbidding boss, Lynn Mason. 'We knew everything,' writes Ferris, and the collective provides a magisterial account of, for instance, doughy-faced Amber's pregnancy by a married associate. The comforting consensus is reinforced in endless, indistinguishable 'creative' meetings (three out of four of which, Ferris notes with dry precision, are redundant).

From the first page, the illusion of community is under attack. The dotcom bubble has burst and days of pushing each other around 'really fast' in a swivel chair give way to a round of layoffs that chips away at the very substance of the narrator. 'We hated not knowing,' the workers complain, denied any potentially actionable rationale for which of them might be next to 'walk Spanish down the hall'. And uncertainty drives an appropriately slight plot: as a rumour circulates that Lynn Mason has breast cancer, a mysterious client demands the besieged team produce ads to 'make cancer patients laugh'.

Recent American accounts of corporate life - Douglas Coupland's Microserfs, Mike Judge's 1999 comedy Office Space, the Dilbert cartoon strip - tend to the mordant. Then We Came to the End is funny, too. It is stomach-turningly accurate on everything from the unsteady 'particleboard wrapped in a cheap orange or beige fiber' between cubicles to the irrational rage that prompts otherwise decentish people to snap 'crip', 'gimp' and 'wobbler' behind an injured colleague's back. But the deadpanning - 'one or two people loved everyone and everything. Those who loved everyone were universally reviled' - is misleading: Then We Came to the End is more tragedy than satire.

The tragedy, though, comes in appropriately small packages. Ferris is brilliant on the pathos of the 'useless shit' that surrounds his workers. In an attenuated world of modular desks and coffee stations, 'our mugs, our mouse pads, our desk clocks, our daily calendars, the contents of our desk drawers' take on a life of their own, alternately hoarded and despised as reminders of hundreds of lost days.

Swaths of the novel are devoted to a baroque theft and exchange of office chairs. Then We Came to the End is preoccupied by the treacherous non-durability of consumer durables. Beyond the revolving security doors lies grander-scale private suffering. But the novel reserves its greatest compassion for the disregarded sadnesses of the office. Roland, the impoverished, superannuated security guard, sits all day long 'at his lonely lobby post' or goes 'back and forth around the building on his aching feet'.

The dead Frank Brizzolera is reduced to 'a Styrofoam coffee cup on the floor under the desk, a cigarette butt curled at the bottom like a dead tequila worm'. The large writ absurdly small is the novel's favourite device, and the tension between them drives its best setpieces. The would-be climactic office massacre - unhinged ex-employee Tom Mota arrives dressed in a clown suit, bellowing Emerson quotations and waving a gun - dissolves in bathos when his bullets turn out to be paint pellets.

'We', or the bits of it that are left, are desperate to escape this poverty of scale. 'There had to be a better story than this one,' they muse, and the escapes that Ferris, a former adman, posits are literary and imaginative. Tom Mota, like a chino-clad Emma Bovary, clings to his romantic heroes, Emerson and Whitman. Don Blattner is working on a screenplay about 'a disaffected and cynical copywriter suffering ennui in the office setting while dreaming of becoming a famous screenwriter'.

Mentioned in passing is quiet Hank Neary, who dresses 'like an Oxford professor' and is working on 'a short, angry book about work'. Characteristically, he turns out to be the novel's heart. Five years later, a reading from his novel duplicates Then We Came to the End's only third-person chapter, an account of inscrutable Lynn Mason's last lonely evening before a mastectomy. Such salvation as there is, Ferris hints, comes from imaginative sympathy with the individual.

It's a neat-handed twist, but its tricksiness is unnecessary. Ferris's descriptions of the ordinary are so good - his workers spend their time lost 'inside long silent pauses as we bent over our desks' - they need no elaboration.